Method for continuously manufacturing composite hollow structure

ABSTRACT

A method is disclosed for continuously manufacturing a composite hollow structure. The method may include continuously coating fibers with a matrix, and revolving matrix-coated fibers about a non-fiber axis. The method may also include diverting the matrix-coated fibers radially outward away from the non-fiber axis, and curing the matrix-coated fibers.

TECHNICAL FIELD

The present disclosure relates generally to a manufacturing method and,more particularly, to a method for continuously manufacturing compositehollow structures.

BACKGROUND

Extrusion manufacturing is a known process for producing continuoushollow structures. During extrusion manufacturing, a liquid matrix(e.g., a thermoset resin or a heated thermoplastic) is pushed through adie having a desired cross-sectional shape and size. The material, uponexiting the die, cures and hardens into a final form. In someapplications, UV light and/or ultrasonic vibrations are used to speedthe cure of the liquid matrix as it exits the die. The hollow structuresproduced by the extrusion manufacturing process may have any continuouslength, with a straight or curved profile, a consistent cross-sectionalshape, and excellent surface finish. Although extrusion manufacturingcan be an efficient way to continuously manufacture hollow structures,the resulting structures may lack the strength required for someapplications.

Pultrusion manufacturing is a known process for producing high-strengthhollow structures. During pultrusion manufacturing, individual fiberstrands, braids of strands, and/or woven fabrics are coated with orotherwise impregnated with a liquid matrix (e.g., a thermoset resin or aheated thermoplastic) and pulled through a stationary die where theliquid matrix cures and hardens into a final form. As with extrusionmanufacturing, UV light and/or ultrasonic vibrations are used in somepultrusion applications to speed the cure of the liquid matrix as itexits the die. The hollow structures produced by the pultrusionmanufacturing process have many of the same attributes of extrudedstructures, as well as increased strength due to the integrated fibers.Although pultrusion manufacturing can be an efficient way tocontinuously manufacture high-strength hollow structures, the resultingstructures may lack the form required for some applications. Inaddition, the variety of fiber patterns integrated within the pultrudedhollow structures may be limited, thereby limiting availablecharacteristics of the resulting hollow structures.

The disclosed method is directed to overcoming one or more of theproblems set forth above and/or other problems of the prior art.

SUMMARY

In one aspect, the present disclosure is directed to a method ofcontinuously manufacturing a hollow structure. The method may includecontinuously coating fibers with a matrix, and revolving matrix-coatedfibers about a non-fiber axis. The method may also include diverting thematrix-coated fibers radially outward away from the non-fiber axis, andcuring the matrix-coated fibers.

In another aspect, the present disclosure is directed to another methodof continuously manufacturing a hollow structure. This method mayinclude continuously coating fibers with a matrix, revolving a firstsubset of the matrix-coated fibers in a first direction, and revolving asecond subset of the matrix-coated fibers in a second direction oppositethe first. The method may also include diverting the matrix-coatedfibers radially outward away from the non-fiber axis, pressing the firstsubset of the matrix-coated fibers against the second subset of thematrix-coated fibers, and curing the matrix-coated fibers. The methodmay further include dynamically adjusting revolving of the first andsecond subsets of the matrix-coated fibers during manufacturing of thecomposite hollow structure, and mechanically pinching the matrix-coatedfibers prior to curing the matrix-coated fibers in order to fix a lengthof the composite hollow structure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 and 2 are diagrammatic illustrations of exemplary disclosedmanufacturing systems;

FIG. 3 is cross-sectional illustration of an exemplary disclosed driveand head that may be used in conjunction with the manufacturing systemsof FIGS. 1 and 2;

FIG. 4 is an exploded view illustration of the head of FIG. 3;

FIG. 5 is a perspective illustration of an exemplary disclosed shieldthat may be connected to the head of FIGS. 3 and 4; and

FIGS. 6-9 are diagrammatic illustrations of exemplary disclosed hollowstructures that may be manufactured with the system of FIGS. 1 and 2;and

FIGS. 10-18 are diagrammatic illustrations of exemplary disclosed weavepatterns at may make up walls of the hollow structures of FIGS. 6-9.

DETAILED DESCRIPTION

FIGS. 1 and 2 illustrate different exemplary systems 10 and 12, whichmay be used to continuously manufacture hollow composite structures(e.g., tubes, hoses, channels, conduits, ducts, etc.) 14 having anydesired cross-sectional shape (e.g., circular or polygonal). Each ofsystems 10, 12 may include a support 16, a drive 18, and a head 20. Head20 may be coupled to support 16 via drive 18. In the disclosedembodiment of FIG. 1, support 16 is a robotic arm capable of movingdrive 18 and head 20 in multiple directions during fabrication ofstructure 14, such that a resulting longitudinal axis 22 of structure 14is three-dimensional. In the embodiment of FIG. 2, support 16 is anoverhead gantry also capable of moving head 20 and drive 18 in multipledirections during fabrication of structures 14. Although supports 16 ofboth embodiments are shown as being capable of 6-axis movements, it iscontemplated that any other type of support 16 capable of moving drive18 and head 20 in the same or a different manner could also be utilized,if desired.

As shown in FIG. 3, drive 18, in addition to functioning as a mechanicalcoupling between head 20 and support 16, may include components thatcooperate to also supply power to head 20. These components may include,among other things, a container 24, one or more actuators disposedinside container 24, and a plurality of links connecting the variousactuators to different portions of head 20. In the disclosed embodiment,three different actuators 26, 28, 30 are shown inside of container 24 asbeing coupled to head 20 by way of two different shafts 32, 34 and a rod36. Actuators 26 and 28 may be rotary-type actuators (e.g., electric,hydraulic, or pneumatic motors), while actuator 30 may be a linear-typeactuator (e.g., a solenoid actuator, a hydraulic cylinder, a lead screw,etc.). Shaft 32 may be tubular (i.e., cylindrical and hollow) and drivenby actuator 26 to rotate about an axis 37, and shaft 34 may pass througha center of shaft 32 and be driven by actuator 28 to also rotate aboutaxis 37. For the purposes of this disclosure, axis 37 may be considereda non-fiber axis of head 20. In the disclosed embodiment, shaft 34 isalso tubular, and rod 36 may be configured to pass through a center ofshaft 34 and be driven by actuator 30 to move axially in-and-out withrespect to shaft 34. Rod 36 may also be generally aligned with axis 37.It is contemplated that a different number of actuators could be coupledwith head 20 by way of a different arrangement of shafts and/or rods, ifdesired. For example, a single actuator could be coupled to rotate bothof shafts 32, 34 (e.g., by way of a gear train—not shown), if desired.Electricity may be provided to actuators 30-34 from an external supply(e.g., an established utility grid) 38.

In addition to functioning as a mounting location for the variousactuators described above, container 24 may also function as a pressurevessel in some embodiments. For example, container 24 may be configuredto receive or otherwise contain a pressurized matrix material. Thematrix material may include any type of liquid resin (e.g., a zerovolatile organic compound resin) that is curable. Exemplary resinsinclude epoxy resins, polyester resins, cationic epoxies, acrylatedepoxies, urethanes, esters, thermoplastics, photopolymers, polyepoxides,and more. In one embodiment, the pressure of the matrix material insidecontainer 24 may be generated by an external device (e.g., an extruderor another type of pump) 40 that is fluidly connected to container 24via a corresponding conduit 42. In another embodiment, however, thepressure may be generated completely inside of container 24 by a similartype of device. In some instances, the matrix material inside container24 may need to be kept cool and/or dark in order to inhibit prematurecuring; while in other instances, the matrix material may need to bekept warm for the same reason. In either situation, container 24 may bespecially configured (e.g., insulated, chilled, and/or warmed) toprovide for these needs.

The matrix material stored inside container 24 may be used to coat anynumber of separate fibers and, together with the fibers, make up a wallof composite structure 14. In the disclosed embodiment, two separatefiber supplies 44, 46 are stored within (e.g., on separate internalspools—not shown) or otherwise passed through container 24 (e.g., fedfrom the same or separate external spools). In one example, the fibersof supplies 44, 46 are of the same type and have the same diameter andcross-sectional shape (e.g., circular, square, flat, etc.). In otherexamples, however, the fibers of supplies 44, 46 are of a differenttype, have different diameters, and/or have different cross-sectionalshapes. Each of supplies 44. 46 may include a single strand of fiber, atow or roving of several fiber strands, or a weave of fiber strands. Thestrands may include, for example, carbon fibers, vegetable fibers, woodfibers, mineral fibers, glass fibers, metallic wires, etc.

The fibers from supplies 44, 46 may be coated with the matrix materialstored in container 24 while the fibers are inside container 24, whilethe fibers are being passed to head 20, and/or while the fibers aredischarging from head 20, as desired. The matrix material, the dryfibers from one or both of supplies 44, 46, and/or fibers already coatedwith the matrix material may be transported into head 20 in any mannerapparent to one skilled in the art. In the embodiment of FIG. 3, thematrix material is mixed with the fibers from both supplies 44, 46, andthe matrix-coated fibers are then directed into head 20 via the openinterior(s) of shaft(s) 32 and/or 34. It is contemplated, however, thatdedicated conduits (not shown) could alternatively be used for thispurpose, if desired. The matrix material may be pushed through shaft(s)32, 34 (and/or the dedicated conduit(s)) by the pressure of container24, and the fibers may travel along with the matrix material.Alternatively or additionally, the fibers (coated or uncoated) may bemechanically pulled through shafts 32 and/or 34, and the matrix materialmay be pulled along with the fibers in some embodiments. In thedisclosed example, electricity is also supplied to head 20 by way of theempty interior(s) of shaft(s) 32 and/or 34.

Head 20 may include a series of cylindrical components nested insideeach other that function to create unique weave patterns in the walls ofstructure 14 out of the matrix-coated fibers received from drive 18. Asseen in FIGS. 3 and 4, these components may include, among other things,a housing 48, one or more fiber guides (e.g., a first fiber guide 50 anda second fiber guide 52), a diverter 54, one or more cure enhancers(e.g., a UV light 56 and/or an ultrasonic emitter 58), and a cutoff 60.As will be explained in more detail below, matrix-coated fibers fromdrive 18 may pass through first and/or second fiber guides 50, 52, wherea rotation in the fibers may be generated. The rotating matrix-coatedfibers may then pass through an annular gap 61 (shown only in FIG. 3)between diverter 54 and housing 48 and around a mouth 62 of diverter 54,where the resin is caused to cure from the inside-out by way of UV light56 and/or ultrasonic emitter 58.

Housing 48 may be generally tubular, and have an open end 64 (shown onlyin FIG. 4) and an opposing domed end 68. An inner diameter of housing 48at open end 64 may be larger than outer diameters of fiber guides 50,52, and an internal axial length of housing 48 may be greater than axiallengths of fiber guides 50, 52. With this arrangement, fiber guides 50,52 may fit at least partially inside housing 48. In the disclosedembodiment, both fiber guides 50, 52 nest completely inside of housing48, such that an axial face 69 of housing 48 at open end 64 extends pastcorresponding ends of fiber guides 50, 52. Face 69 of housing 48 at openend 64 may be convexly curved to mirror a correspondingly curved outersurface of diverter 54. A center opening 70 may be formed within domedend 68 of housing 48, allowing shaft 32, shaft 34, and rod 36 to passaxially therethrough. In some embodiments, a seal 72 (e.g., ano-ring—shown only in FIG. 3) may be disposed at opening 70 and aroundshaft 32 to inhibit liquid matrix material from leaking out of housing48.

Fiber guides 50 and 52, like housing 48, may also be generally tubularand have an open end 74 and a domed end 76 located opposite open end 74.An inner diameter of fiber guide 50 at open end 74 may be larger than anouter diameter of fiber guide 52 at domed end 76, and an internal axiallength of fiber guide 50 may be greater than an external axial length offiber guide 52. With this arrangement, fiber guide 52 may fit at leastpartially inside fiber guide 50. In the disclosed embodiment, fiberguide 52 nests completely inside of fiber guide 50, such that an endface 78 of fiber guide 50 at open end 74 extends axially past an endface 80 of fiber guide 52. End faces 78 and 80 of fiber guides 50, 52may be convexly curved to mirror the correspondingly curved outersurface of diverter 54.

Fiber guides 50 and 52 may each have an annular side wall 82 thatextends from open end 74 to domed end 76. In the disclosed example, athickness of each side wall 82 may be about the same within engineeringtolerances). However, it is contemplated that each side wall 82 couldhave a different thickness, if desired. The thickness of side walls 82may be sufficient to internally accommodate any number of axiallyoriented passages 84. Passages 84 may pass from the corresponding endface (i.e., end face 78 or 80) completely through domed end 76. Eachpassage 84 formed in fiber guide 50 may be configured to receive one ormore fibers from one of supplies 44. 46, while each passage 84 formed infiber guide 52 may be configured to receive one or more fibers from theother of supplies 44, 46. It is contemplated that the same or adifferent number of passages 84 may be formed within each of fiberguides 50 and 52, as desired, and/or that passages 84 may have the sameor different diameters. In the disclosed embodiment, twenty-four equallyspaced passages 84 having substantially identical diameters are formedin each of fiber guides 50, 52. Because annular wall 82 of fiber guide52 may have a smaller diameter than annular wall 82 of fiber guide 50,the equal spacing between passages 84 within fiber guide 52 may bedifferent than the corresponding equal spacing between passages 84within fiber guide 50. It should be noted that passage spacing withinone or both of fiber guides 50, 52 could be unequally distributed insome embodiments. Because fiber guide 52 may nest completely insidefiber guide 50, the fibers passing through fiber guide 50 may generallybe overlapped with the fibers passing through fiber guide 52 duringfabrication of structure 14.

Each of fiber guides 50, 52 may be selectively rotated or heldstationary during fabrication of structure 14, such that the fiberspassing through each guide together create unique weave patterns (e.g.,spiraling patterns, oscillating patterns, straight and parallelpatterns, or combination patterns). The rotation of fiber guide 50 maybe driven via shaft 32, while the rotation of fiber guide 52 may bedriven via shaft 34. Shaft 32 may connect to domed end 76 and/or to aninternal surface of fiber guide 50. Shaft 34 may pass through aclearance opening 86 in domed end 76 of fiber guide 50 to engage domedend 76 and/or an internal surface of fiber guide 52. As will bedescribed in more detail below, the relative rotations of fiber guides50, 52 may affect the resulting weave patterns of structure 14. Inparticular, the rotations of fiber guides 50, 52 may be in the samedirection, counter to each other, continuous, intermittent, oscillating,have smaller or larger oscillation ranges, be implemented at lower orhigher speeds, etc., in order to produce unique and/or dynamicallychanging weave patterns having desired properties. In addition, therotations of fiber guides 50, 52 may be choreographed with the movementsof support 16, with the movements of diverter 54, with an axialextrusion distance and/or rate, and/or with known geometry of structure14 (e.g., termination points, coupling points, tees, diametricalchanges, splices, turns, high-pressure and/or high-temperature areas,etc.).

In the disclosed embodiment, diverter 54 is generally bell-shaped andhas a domed end 88 located opposite mouth 62. Domed end 88 may have asmaller diameter than mouth 62 and be configured to nest at leastpartially within fiber guide 52. Mouth 62 may flare radially outwardfrom domed end 88, and have an outer diameter larger than an outerdiameter of fiber guide 52. In one embodiment, the outer diameter ofmouth 62 may be about the same as an outer diameter of housing 48.Diverter 54, due to its outwardly flaring contour, may function todivert the fibers exiting passages 84 of both fiber guides 50, 52radially outward. In this manner, a resulting internal diameter ofstructure 14 may be dictated by the outer diameter of diverter 54. Inaddition, diverter 54 may divert the fibers against face 69 of housing48, thereby sandwiching the fibers within gap 61 (referring to FIG. 3).Accordingly, the diverting function of diverter 54, in addition toestablishing the internal diameter of structure 14, may also dictate thewall thickness of structure 14. It is contemplated that diverter 54could have a different shape (e.g., conical, pyramidal, etc.), ifdesired.

In one embodiment, diverter 54 may be movable to selectively adjust thewall thickness of structure 14. Specifically, rod 36 may pass throughclearance openings 86 of fiber guides 50, 52 to engage domed end 76 ofdiverter 54. With this connection, an axial translation of rod 36 causedby actuator 30 (referring to FIG. 3) may result in a varying width ofgap 61 and a corresponding wall thickness of structure 14. Accordingly,thicker walls of structure 14 may be fabricated by pushing diverter 54away from housing 48, and thinner walls may be fabricated by pullingdiverter 54 closer to housing 48.

It is contemplated that particular features within the walls ofstructure 14 may be created by rapidly changing the width of gap 61(i.e., by rapidly pulling diverter 54 in and rapidly pushing diverter 54back out). For example, ridges (see FIG. 8), flanges (See FIG. 7),flexible sections, and other features may be created by adjusting thespeed and duration of the pulling/pushing motions.

It is contemplated that a fill material (e.g., an insulator, aconductor, an optic, a surface finish, etc.) could be deposited withinthe hollow interior of structure 14, if desired, while structure 14 isbeing formed. For example, rod 36 could be hollow (e.g., like shafts 32,34) and extend through a center of any associated cure enhancer. Asupply of material (e.g., a liquid supply, a foam supply, a solidsupply, a gas supply, etc.) could then be connected with an end of rod36 inside housing 34, and the material would be forced to dischargethrough rod 36 and into structure 14. It is contemplated that the samesure enhancer used to cure structure 14 could also be used to cure thefill material, if desired, or that another dedicated cure enhancer (notshown) could be used for this purpose. In one particular embodiment, theportion of rod 36 that extends past the cure enhancer and into theinterior of structure 14 could be flexible so that engagement withstructure 14 would not deform or damage structure 14. In the same oranother embodiment, rod 36 may extend a distance into structure 14 thatcorresponds with curing of structure 14.

UV light 56 may be configured to continuously expose an internal surfaceof structure 14 to electromagnetic radiation during the formation ofstructure 14. The electromagnetic radiation may increase a rate ofchemical reaction occurring within the matrix material dischargingthrough gap 61, thereby helping to decrease a time required for thematrix material to cure. In the disclosed embodiment, UV light 56 may bemounted within mouth 62 of diverter 54 in general alignment with axis37, and oriented to direct the radiation away from diverter 54. UV light56 may include multiple LEDs (e.g., 6 different LEDs) that are equallydistributed about axis 37. However, it is contemplated that any numberof LEDs or other electromagnetic radiation sources could alternativelybe utilized for the disclosed purposes. UV light 56 may be powered viaan electrical lead 90 that extends from supply 38 (referring to FIG. 3)through shafts 32, 34 and rod 36. In some embodiments, rod 36 may itselffunction as electrical lead 90. The amount of electromagnetic radiationmay be sufficient to cure the matrix material before structure 14 isaxially extruded more than a predetermined length away from mouth 62. Inone embodiment, structure 14 is completely cured before the axialextrusion length becomes equal to an external diameter of structure 14.

Ultrasonic emitter 58 may be used in place of or in addition to UV light56 to increase the cure rate of the matrix material in structure 14. Forexample, ultrasonic emitter 58 could be mounted directly inside mouth 62of diverter 54 or alternatively mounted to (e.g., within a correspondingrecess of) a distal end of UV light 56. Ultrasonic emitter 58 may beused to discharge ultrasonic energy to molecules in the matrix material,causing the molecules to vibrate. The vibrations may generate bubbles inthe matrix material, which cavitate at high temperatures and pressures,which force the matrix material to cure quicker than otherwise possible.Ultrasonic emitter 58 may be powered in the same manner as UV light 56,and also function to cure structure 14 from the inside-out. It iscontemplated that, in addition to or in place of UV light 56 and/orultrasonic emitter 58, One or more additional cure enhancers (not shown)could be located to help speed up a cure rate of structure 14 from theoutside-in, if desired.

Cutoff 60 may be used to selectively terminate or otherwise fix a lengthof structure 14 during manufacturing thereof. As shown in FIGS. 3 and 4,cutoff 60 may be generally ring-like, and moveably mounted to anexternal surface of housing 48. Cutoff 60 may have a sharpened edge 92that is configured to slide along axis 37 until it engages thematrix-coated fibers discharging through gap 61. Further sliding in thesame direction may then function to shear the fibers against mouth 62,thereby fixing a length of structure 14. It should be noted that thisshearing action may take place only while the matrix material is stilluncured, such that a force required to push edge 92 through the fibersof structure 14 may be lower and a resulting cut surface may have afiner finish.

The axial movement of cutoff 60 may be generated by a dedicated actuator93 (see FIG. 3). Actuator 93 may be mounted to housing 48 and embody alinear actuator (e.g., a hydraulic piston or a solenoid) or a rotaryactuator (e.g., a motor that engages external threads on housing 48), asdesired. Actuator 93 may receive electrical power from supply 38 viaexternal wiring.

In some embodiments, the motion of cutoff 60 may be coordinated with themotion of diverter 54 during the fiber shearing of structure 14. Forexample, just prior to or during the axial movement of cutting edge 92toward the fibers of structure 14, diverter 54 may be pulled inwardtoward housing 48 by rod 36 and actuator 30. By pulling diverter 54inward, a wall thickness of structure 14 may be reduced and thereby madeeasier to shear. In addition, by pulling diverter 54 inward, a greaterclamping force may be exerted on the fibers, thereby reducing therequired shearing force and/or movement of cutting edge 92.

Even though the matrix-coated fibers of structure 14 may be quicklycured after discharge through gap 61, the speed of this cure may beinsufficient for some applications. For example, when manufacturingstructure 14 under water, in space, or in another inhospitableenvironment of unideal (e.g., severe or extreme) temperatures, unidealpressures, and/or high-contamination, the matrix-coated fibers should beshielded from the environment until the cure is complete so as to ensuredesired structural characteristics. For this reason, a shield 94 may beprovided and selectively coupled to a distal end of head 20. Anexemplary shield 94 is shown in FIG. 5 as including a flexible coupling.In this embodiment, shield 94 may have a first end 96 having a diameterlarge enough to internally receive and seal the distal end of head 20,and a second end 98 having a diameter large enough to internally receiveand seal around structure 14. A length of shield 94 may be sufficient toprovide a desired curing time for structure 14, such that the portion ofstructure 14 engaged by second end 98 is sufficiently cured and will notbe deformed by the engagement. Shield 94 may provide a more controlledenvironment for structure 14, allowing the matrix therein to cure by adesired amount prior to structure 14 being exposed to the inhospitableenvironment. In some embodiments, shield 94 may be pressurized with aninert gas, pressurized with a gas that increases a cure rate of thematrix, and/or depressurized to more fully control the environmentsurrounding structure 14 during manufacture. Shield 94 may be flexible,allowing for structure 14 to bend and curve relative to axis 37(referring to FIG. 3) as it is extruded from head 20.

System 10 may be capable of producing many different weave patternswithin the walls of structure 14. FIGS. 6-9 illustrate exemplarystructures 14 that may be possible to manufacture with system 10. FIGS.10-18 illustrate examples of weave patterns that may be used to makestructure 14. FIGS. 6-18 will be discussed in more detail in thefollowing section to further illustrate the disclosed concepts.

INDUSTRIAL APPLICABILITY

The disclosed systems may be used to continuously manufacture compositestructures having any desired cross-sectional shape and length. Thecomposite structures may include any number of different fibers of thesame or different types and of the same or different diameters. Inaddition, the weave patterns used to make the composite structures maybe dynamically changed during manufacture of the structures (e.g.,without interrupting extrusion of structure 14), Operation of system 10will now be described in detail.

At a start of a manufacturing event, information regarding a desiredhollow structure 14 may be loaded into system 10 (e.g., into acontroller responsible for regulating operations of support 16,actuators 26-28, and/or extruder 40). This information may include,among other things, a size (e.g., diameter, wall thickness, length,etc.), a contour (e.g., a trajectory of axis 22) surface features (e.g.,ridge size, location, thickness, length; flange size, location,thickness, length; etc.), connection geometry (e.g., locations and sizesof couplings, tees, splices, etc.), desired weave patterns, and weavetransition locations. It should be noted that this information mayalternatively or additionally be loaded into system 10 at differenttimes and/or continuously during the manufacturing event, if desired.Based on the component information, one or more different fibers and/orresins may be selectively installed into system 10. Installation of thefiber(s) may include threading of the fiber(s) through shafts 32, 34,through passages 84 in guides 50, 52, and through gap 61. In someembodiments, the fiber(s) may also need to be connected to a pullingmachine (not shown) and/or to a mounting fixture (not shown).Installation of the matrix material may include filling of container 24and/or coupling of extruder 40 to container 24. In some embodiments,depending on the gathered component information, diverters having largeror smaller diameters, and any number of different configurations offiber guides may be selectively used with head 20.

The component information may then be used to control operation ofsystem 10. For example, the fibers may be pulled and/or pushed alongwith the matrix material from head 20 at a desired rate at the same timethat drive 18 causes fiber guides 50, 52 to rotate. During thisrotation, diverter 54 may also be caused to move in or out, and anyavailable cure enhancers (e.g., UV light 56 and/or ultrasonic emitter58) may be activated to cure the matrix material. Support 16 may alsoselectively move head 20 in a desired manner, such that axis 22 of theresulting hollow structure 14 follows a desired trajectory. Oncestructure 14 has grown to a desired length, cutoff 60 may be used tosever structure 14 from system 10 in the manner described above.

FIG. 6 illustrates one example of structure 14 that may be produced bysystem 10. As can be seen in this figure, axis 22 of structure 14 may betranslated and/or rotated (e.g., via corresponding movements of head 20)in any direction during the lengthwise growth of structure 14 to producecomplex geometry. In addition, the weave pattern of structure 14 may bechoreographed with the changing geometry. In the example of FIG. 6, anelbow has been created having multiple weave patterns that transitionaround a corner section 100. Specifically, the fibers passing throughone of guides 50 or 52 oscillate at opposing ends of corner section 100,but straighten out (i.e., align with axis 22) inside of corner section100. At the same time, the fibers passing through the other of guides 50or 52 remain straight throughout the length of structure 14. Inaddition, a frequency of the oscillating fibers may vary. In particular,the oscillating fibers may oscillate at a slower frequency for a section102, and then at a higher frequency for a section 104. Thisfrequency-changing pattern may be repetitive in some applications.

It is contemplated that the weave pattern used at any particular pointalong the length of structure 14 may be selected in order to providedesired characteristics at the corresponding point. For example,oscillating patterns may be effectively used where slight movementand/or flexing of structure 14 is desired and/or expected over small andlarge distances. One application where oscillating patterns could behelpful may include the manufacture of a gas pipeline over arctic tundrafor many continuous miles. In this application, the freezing and thawingof the tundra could cause undesired movements of the pipeline that mustbe accommodated in order to avoid cracking of the pipeline. Themovements may be accommodated via the oscillating weave pattern. Theoscillating weave pattern may also add toughness and or abrasionresistance to structure 14. The fibers within section 100 may all beparallel in order to produce a different characteristic within structure14. For example, parallel fibers may provide for high static strength,where little or no bending is desired or expected.

FIG. 7 illustrates another example of structure 14 that may be producedby system 10. As can be seen in this figure, a coupling 106 is used at aterminal end of structure 14 to connect structure 14 to another device(not shown) or to otherwise close off the end of structure 14. The useof coupling 106 may require different characteristics (e.g., greaterstrength or stiffness) in the walls of structure 14 and, thus, the weavepattern and/or thickness of structure 14 may change at the couplinglocation in a corresponding way. For instance, the weave pattern maybecome denser at this location and/or the wall thickness may increase.The weave pattern may become denser by increasing an oscillationfrequency for a given axial growth rate (i.e., for a given extrusionrate) and/or by increasing an oscillation range. The wall thickness mayincrease at this location by causing diverter 54 to be pushed furtheraway from housing 48, such that gap 61 becomes larger.

FIG. 8 illustrates another example of structure 14 that may be producedby system 10. As can be seen in this figure, the geometry of structure14 changes (e.g., necks down) at a transition location 108 and at aterminal location 110. These geometry changes may involve correspondingchanges in the weave pattern and/or in an outer profile of structure 14.For instance, the weave pattern at transition location 108 may changefrom oscillating and parallel fibers to only parallel fibers (oralternatively to only oscillating fibers). In addition, ridges 112 maybe formed at terminal location 110 via the rapid in/out movements ofdiverter 54. The parallel fibers may enhance a rigidity at transitionlocation 108, while ridges 112 may facilitate connection with anotherstructure.

FIG. 9 illustrates a final example of structure 14 that may be producedby system 10. As can be seen in this figure, the geometry of structure14 does not necessarily change. However, changes in the weave pattern ofstructure 14 may still be varied for application-specific purposes. Inparticular, a specific portion 114 of structure 14 may have differentcharacteristics than other portions 116 of the same structure, eventhough all portions have the same general geometry. For instance, agreater resistance to external temperatures and/or pressures may berequired within portion 114; a greater abrasion resistance may berequired; and/or a greater flexibility and/or rigidity may be required.These characteristics may be provided by way of varying weave patterns.In the disclosed example, the weave pattern within portion 114 includesparallel fibers on only one section (e.g., one halt) and a density ofoscillating fibers on remaining sections that is different than a fiberdensity within portions 116.

FIGS. 10-18 illustrate exemplary weave patterns that may be used at anylocation on any structure 14, regardless of structure 14 having changinggeometry or characteristic requirements. In FIG. 10, a pattern 118 usesspiraling fibers 120 from guide 50 and spiraling fibers 122 from guide52. Spiraling patterns of fibers are known to increase a resistance tointernal pressures. At a top of pattern 118, fibers 120 may be equallyinterleaved with fibers 122 and may be identical fibers or fibers ofdifferent diameters, shapes, and/or sizes, as desired. About midway downpattern 118, however, the fibers may transition to a different weave,wherein two of fibers 122 are immediately adjacent each other. This newpattern may be achieved, for example, by increasing a rotational rate ofguide 52 to be twice the rotational rate of guide 50.

In FIG. 11, a pattern 124 is created that transitions from both offibers 120, 122 spiraling in a first direction to one of fibers 120, 122spiraling in a different direction. A similar pattern 126 is shown inFIG. 12, but instead of one of fibers 120, 122 transitioning to adifferent direction, both of fibers 120, 122 transition to the differentdirection. Another similar pattern 128 is shown in FIG. 13, but insteadof only one of fibers 120, 122 transitioning to spiraling in a differentdirection, one of fibers 120, 122 transitions to oscillating rather thanspiraling.

In FIG. 14, a pattern 130 is created that includes both of fibers 120and 122 oscillating in a relatively synchronized manner. Thissynchronicity may involve both fibers 120, 122 oscillating at about thesame frequency, in phase with each other, and through the same ranges.FIG. 15 shows a pattern 132, wherein fibers 120 and 122 are oscillatingout of phase with each other using essentially the same frequency andrange. However, one of fibers 120, 122 transitions about half-way alongthe length of pattern 132 to oscillate at a different frequency and/orthrough a different range. In FIG. 16, a pattern 134 is shown as havingfibers 120 and 122 oscillating out of phase using essentially the samefrequency and range. However, one or both of fibers 120, 122 may shiftradial locations about half-way along the length of pattern 134 to movefrom being overlapping to being adjacent to each other.

In a pattern 136 of FIG. 17, one of fibers 120, 122 is shown as beingstraight and generally aligned with axis 22 (referring to FIGS. 1 and2), while the other of fibers 120, 122 is initially spiraling at anupper-half of pattern 136. The spiraling fiber 120 or 122 thentransitions to oscillating at a lower-half of pattern 136. In a pattern138 of FIG. 18, all of fibers 120, 122 are straight and aligned withaxis 22, and equally interleaved with each other.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the disclosed method. Otherembodiments will be apparent to those skilled in the art fromconsideration of the specification and practice of the disclosed method.It is intended that the specification and examples be considered asexemplary only, with a true scope being indicated by the followingclaims and their equivalents.

What is claimed is:
 1. A method of continuously manufacturing acomposite hollow structure, comprising: continuously coating fibers witha matrix; revolving matrix-coated fibers about a non-fiber axis;diverting the matrix-coated fibers radially outward away from thenon-fiber axis; and curing the matrix-coated fibers.
 2. The method ofclaim 1, wherein revolving matrix-coated fibers includes: revolving afirst subset of the matrix-coated fibers in a first direction; andrevolving a second subset of the matrix-coated fibers in a seconddirection opposite the first.
 3. The method of claim 2, whereinrevolving the first and second subsets of matrix-coated fibers includessynchronously oscillating the first and second directions.
 4. The methodof claim 2, wherein revolving the first and second subsets ofmatrix-coated fibers includes revolving the first and second subsets ofmatrix-coated fibers through a range of up to 180°.
 5. The method ofclaim 4, wherein revolving the first and second subsets of matrix-coatedfibers includes revolving the first and second subsets of matrix-coatedfibers through a range of about 15° to about 30°.
 6. The method of claim2, wherein revolving the first and second subsets of the matrix-coatedfibers includes revolving the first subset of the matrix-coated fibersthrough a range different than a revolving range of the second subset ofthe matrix-coated fibers.
 7. The method of claim 2, wherein revolvingthe first and second subsets of the matrix-coated fibers includescontinuously revolving the first subset of the matrix-coated fibers inthe first direction and selectively oscillating a revolving direction ofthe second subset of the matrix-coated fibers.
 8. The method of claim 2,wherein revolving the first and second subsets of the matrix-coatedfibers includes revolving the first subset of the matrix-coated fibersat a first rate and revolving the second subset of the matrix-coatedfibers at a second rate.
 9. The method of claim 8, further includingdynamically adjusting the first and second rates during manufacturing ofthe composite hollow structure.
 10. The method of claim 2, furtherincluding dynamically adjusting a pattern of weave created by revolvingthe first and second subsets of matrix-coated fibers duringmanufacturing of the composite hollow structure.
 11. The method of claim2, further including pressing the first subset of the matrix-coatedfibers against the second subset of the matrix-coated fibers.
 12. Themethod of claim 11, further including varying the pressing to therebyadjust a wall thickness of the composite hollow structure.
 13. Themethod of claim 2, wherein the first subset of the matrix-coated fibershas at least one of a different diameter and a different material typethan the second subset of the matrix-coated fibers.
 14. The method ofclaim 2, wherein the first subset of the matrix-coated fibers has adifferent type of matrix than the second subset of the matrix-coatedfibers.
 15. The method of claim 1, wherein curing the matrix-coatedfibers includes curing the matrix-coated fibers from inside thecomposite hollow structure.
 16. The method of claim 1, wherein curingthe matrix-coated fibers includes directing at least one of UV light andultrasonic vibrations toward the matrix-coated fibers.
 17. The method ofclaim 16, further including controlling an environment of thematrix-coated fibers for a period of time during and after the at leastone of the UV light and the ultrasonic vibrations are directed towardthe matrix-coated fibers.
 18. The method of claim 1, further includingmechanically pinching the matrix-coated fibers prior to curing thematrix-coated fibers in order to fix a length of the composite hollowstructure.
 19. The method of claim 1, further including filling aninterior of the composite hollow structure as the hollow structure iscuring.
 20. A method of continuously manufacturing a composite hollowstructure, comprising: continuously coating fibers with a matrix;revolving a first subset of the matrix-coated fibers in a firstdirection; and revolving a second subset of the matrix-coated fibers ina second direction opposite the first; diverting the matrix-coatedfibers radially outward away from the non-fiber axis; pressing the firstsubset of the matrix-coated fibers against the second subset of thematrix-coated fibers; curing the matrix-coated fibers; dynamicallyadjusting revolving of the first and second subsets of the matrix-coatedfibers during manufacturing of the composite hollow structure; andmechanically pinching the matrix-coated fibers prior to curing thematrix-coated fibers in order to fix a length of the composite hollowstructure.